• By Robert Preidt HealthDay Reporter
• Posted June 3, 2022

Surprising Factors That Raise (or Lower) Your Odds for COVID-19

A new study offers some unexpected conclusions about what factors might influence your chances of getting COVID-19.

What did it find? People with food allergies have a lower risk of infection than those without them do, while asthma does not affect risk one way or the other. Meanwhile, obesity and having a high BMI do boost the chances of catching COVID.

Children aged 12 and younger were just as likely to become infected as teens and adults, but three-quarters of infections in children are asymptomatic, according to the study. It also confirmed that COVID transmission in households with children is high.

The U.S. National Institute of Allergy and Infectious Diseases (NIAID)-funded study included more than 4,000 people in nearly 1,400 households with at least one person age 21 or younger. They lived in 12 U.S. cities and were monitored between May 2020 and February 2021, before COVID-19 vaccines became widely available to people other than health care workers and before the widespread emergence of variants of concern.

Earlier research suggested that having an allergic disease might reduce a person's susceptibility to COVID infection, and the latest study found that having a food allergy halved the risk of infection, but asthma and other allergic conditions such as eczema and allergic rhinitis did not change risk.

Why might food allergies be protective?

Type 2 inflammation is a characteristic of allergic conditions and may reduce levels of a protein called the ACE2 receptor on the surface of airway cells. SARS-CoV-2 uses this receptor to enter cells, so lower levels of it could limit the virus's ability to infect the cells, the researchers explained.

Previous studies have shown that obesity is a risk factor for severe COVID-19, and this study found that every 10-point increase in BMI (body mass index, a measure of weight in relation to height) increased the risk of infection by 9%. People who were overweight or obese had a 41% greater risk of infection than those of normal weight.

Proximity to an infected person also played a part: In 58% of households where one person became infected, SARS-CoV-2 was transmitted to multiple members of the household.

Young children may be very efficient COVID transmitters within a household due to their high rate of asymptomatic infection, their potentially high viral loads, and their close physical interactions with family members, the researchers concluded.

The findings "underscore the importance of vaccinating children and implementing other public health measures to prevent them from becoming infected with SARS-CoV-2, thus protecting both children and vulnerable members of their household from the virus," NIAID Director Dr. Anthony Fauci said in an institute news release.

"Furthermore, the observed association between food allergy and the risk of infection with SARS-CoV-2, as well as between body mass index and this risk, merit further investigation," he added.

The findings were published May 31 in the Journal of Allergy and Clinical Immunology.

More information

The U.S. Centers for Disease Control and Prevention outlines how to protect yourself and others from COVID-19.

SOURCE: U.S. National Institute of Allergy and Infectious Diseases, news release, June 1, 2022